The present invention relates to photonic component packages, and more particularly to methods of fabricating photonic component packages with reduced footprint requirements.
Photonic components are of increased benefit when reduced in size and cost. The cross-sectional area of a surface of an electronic module, subsystem, or system that is taken up by, or devoted to, a certain photonic component is referred to as the footprint of that component. The footprint required to couple or interface a photonic component with a printed circuit board or an electronic circuit, module, system, subsystem or socket is typically related to the design of the package of the component that encloses the photonic and electronic elements of the device. In particular, the need to couple or attach photonic elements, such as optical fibers, to photonic components creates needs in the art for improvement in the design of photonic component packages.
Kato, et al., in xe2x80x9cOptical module, method for manufacturing optical module and optical communication apparatusxe2x80x9d, U.S. Pat. No. 6,282,352 (Aug. 28, 2001) disclose a method to form an optical module with a plastic package by molding resin around an optical device and an optical fiber. Kato et al. provide a package having high rigidity and low thermal expansion properties. But the disclosure of Kato et al. fails to consider or provide optional orientations for insertion of the package into a larger system. Kato et al. does not address the advantages of installing the package onto a printed circuit board after high temperature manufacturing steps of the printed circuit board are completed.
Iida et al. disclose, in U.S. Pat. No. 6,186,673, xe2x80x9cPackage for optical semiconductor module,xe2x80x9d Feb. 13, 2001, an improvement in mounting an optical semiconductor module onto a printed circuit board. The improvement of Iida et al. enables a system designer to orient the optical module in a range of orientation angles relative to a high frequency circuit board. Iida et al. does not enable the low cost application of conventional and low cost package manufacturing methods and suitable materials known in the art, such as ceramic or plastic.
Hoang-Phong La discloses, in International Patent Application (PCT) No. WO 00/60673 (Publication Date: Oct. 12, 2000) entitled xe2x80x9cAn electro-optical package for reducing parasitic effectsxe2x80x9d, a package design that allows photonic and electrical signals to be received processed, and responded to with an electrical or a photonic resultant signal. La teaches that his invention can be embodied in a standard and low cost package type and style. Yet La""s work is limited to the provision of a device that accepts and emits electrical and photonic signals via a plurality of electricity-to-light and light-to-electricity converters and wherein all of the converters are aligned along the same side of a substrate. La fails to provide or consider a generally applicable package or packaging technique that enables a coupling of a photonic element, e.g., an optical fiber, or a collimator, with a MEMS or semiconductor device and within or via a low cost and standard package size and type.
There is, therefore, a long felt need to provide a photonic component packages with reduced footprint requirements and that allow for employing low cost manufacturing techniques and may be attached to a socket, a printed circuit board or other appropriate system or module known in the art.
It is an object of the present invention to provide a package for a photonic component.
It is an object of certain preferred embodiments of the present invention to provide a photonic component package having a reduced footprint requirement for mounting onto a module and coupling to one or more optical fibers, wherein a length of at least one the optical fiber proximate to the photonics component package is substantially parallel to a mounting surface of the module.
It is another object of certain preferred embodiments of the present invention to provide a packaging method for fabricating photonic components.
It is yet another object of certain preferred embodiments of the present invention to provide a package that partially or entirely encloses a semiconductor die, such as a photonic element or a micro-electromechanical system die.
It is an object of yet other certain alternate preferred embodiments of the present invention to provide a photonic component that comprises a low cost package, the package substantially complying with a suitable semiconductor industry package standard known in the art.
It is an object of certain still other preferred embodiments of the present invention to provide a photonic component with die attachment performed by certain suitable semiconductor industry standard die attach equipment.
It is an object of certain yet other alternate preferred embodiments of the present invention to provide a method of packaging a photonic component having wire bonds formed by certain suitable semiconductor industry standard wire bonding equipment.
It is an object of certain even other alternate preferred embodiments of the present invention to provide a method of packaging photonic components by certain suitable semiconductor industry standard packaging equipment.
It is an object of certain yet other alternate preferred embodiments of the present invention to provide a method of lid attachment of photonic component packages by certain suitable semiconductor industry lid attach equipment.
It is an object of certain other alternate preferred embodiments of the present invention to provide a method of marking of photonic component packages by certain suitable semiconductor industry marking equipment.
It is an object of certain still other alternate preferred embodiments of the present invention to provide photonic components at least partially testable by certain suitable semiconductor industry standard test equipment.
It is an object of certain yet other alternate preferred embodiments of the present invention to provide photonic components mounted onto printed circuit boards by certain suitable semiconductor industry standard mounting equipment.
It is an object of certain other alternate preferred embodiments of the present invention to provide a boot that at least partially encloses a photonic element coupled with a photonic component package, and wherein the boot and the photonic component package have increased mechanical stability when the photonic component package is attached to a module.
It is an object of the present invention to provide a package for a photonic component that (1) presents a reduced footprint requirement, (2) that enables an optical coupling of a photonic element and a semiconductor die, and (3) supports electrical communications between the semiconductor die module, the module comprising a printed circuit board, an electronic circuit, subsystem or system. A footprint of the package is defined as the cross-sectional area of the module, or of a mounting surface of the module, that is required to be available for use in mounting the present invention to the module.
The preferred embodiment, or invented package, is a low cost package that includes a package body having an interior with a cavity, a photonic element side. A plurality of pins of the invented package extend from the package body. The pins are oriented to not increase the footprint requirement of the present invention beyond that required by the present invention with the pins removed. The projections of the pins reside wholly within the footprint of the package body and the pins do not expand the footprint of the invented package beyond a footprint of the package body. Each pin comprises a substantially straight section.
An external photonic element, such as an optical fiber, is coupled to the invented package and is positioned to establish a parallel orientation with the mounting surface of the module when the pins are inserted into the module. Each pin comprises a substantially straight section.
The term module as defined in reference to the present invention include passive and/or active mechanical, optical, photonic, or electronic hardware and circuitry, including or comprising, but not limited to, an electronic equipment, a printed circuit (xe2x80x9cPCxe2x80x9d) board, a socket, an electronic circuit, a photonic circuit, an electronic system subsystem, and a photonic system or subsystem.
The photonic component may be a variable optical attenuator (xe2x80x9cVOAxe2x80x9d), an optical switch, an optical filter, a multiplexer, a demultiplexer, an add-drop optical signal filter, or other suitable optical or photonic devices or circuits known in the art. It is another object of the present invention to provide a method of packaging photonic components.
A through hole permits access by light from the photonic element side of the package to and/or from the die photonic element along an optical axis of and extending from a length of the photonic element proximate to the through hole. The through hole passes entirely through the lid or the package body and to the cavity. A die is attached within the cavity. The die includes a diced or separated portion of an initial semiconductor wafer. The initial semiconductor wafer is formed with two wafer planar sides. The semiconductor die is then cut, diced, or otherwise separated from the initial wafer. The thickness of the die is smaller than either the width or breadth of the die""s portions of each wafer planar side. Electrical contact pads are located on the one planar side of the die and a die photonic element, such as a movable mirror, photodiode, or laser, is coupled to the same planar side or the other planar side of the die. A package lid substantially covers the cavity, whereby the die is essentially enclosed within the package. Three pins are attached to and extend generally perpendicularly from a pinout side of the package. The pins may be attached on the pinout side along a line. The projections of the pins onto the pinout side reside wholly within a footprint of the package body. The pins do not expand the footprint of the invented package beyond the footprint of the package body. The pins are electrically coupled with the die via wire bonds between the package body and the electrical contact pads of the die. Electrical power, control and communications signals pass to and from the module, such as a PC board, and to the die via the pins. The position and/or state of the die photonic element is controlled or affected by the control signals sent to the die via the pins. The die is positioned within the photonic component package approximately parallel to the pins, wherein at least one of the planar sides of the die is approximately parallel to at least one of the pins.
In the invented package a photonic inlet is mechanically attached to the photonic element side, or element side, of the package. The element side and the pinout side lie in substantially orthogonal planes, whereby the element side is located approximately at a right angle to the element side. A collimator may be attached to the photonic inlet, and at least one optical fiber and/or one photonic element may be attached to the collimator. The optical fiber and/or the photonic element are positioned relative to the die photonic element to interact or couple with the optical fiber and the photonic element.
The term parallel when applied herein to an orientation between the photonic inlet and a mounting surface of a module denotes an orientation between the mounting surface and the photonic inlet that supports or imposes a parallel orientation between an optical axis of a photonic element and the mounting surface when the photonic element is coupled with the photonic inlet.
A second preferred embodiment, or an invented VOA package, provides a package that optically couples a photonic MEMS die and at least two optical fibers. The photonic MEMS die is enclosed within the package body and lid, and the at least two optical fibers are coupled with the photonic inlet via a dual fiber or multi-fiber collimator, as appropriate. The lid and package body of the invented VOA package encloses the MEMS die. The MEMS die is attached to the package using suitable standard die attach equipment and techniques known in the art. The MEMS die is wire bonded to wire bond pads located in the package. The wire bonding is accomplished with standard wire bonding equipment and applying a suitable wire bonding technique known in the art. The wire bond pads are electrically connected with the pins via traces.
The invented VOA package is designed and sized in conformance with one or more standard semiconductor industry materials, sizing and design standards such that the invented VOA package may be formed, fabricated, assembled, wire bonded, packaged, marked, tested and attached to the PC board with suitable semiconductor industry standard materials, equipment and/or methods. The lid is attached to the package body with standard semiconductor industry lid attach equipment. The invented VOA package is marked with standard semiconductor industry marking equipment. Various preferred embodiments of the package may comprise suitable plastic, metallo-ceramic, or metal-glass, or other suitable materials, known in the art. The photonic inlet is approximately or substantially parallel to a mounting surface of the mounting module, whereby an optical axis of each of the optical fibers is, at a point of photonic coupling between the optical fibers and the semiconductor die, approximately or substantially parallel to the mounting surface of the module.
A third preferred embodiment of the present invention further comprises a boot, wherein the boot protects and at least partially encloses an external photonic element and a photonic inlet, and enables the photonic coupling of the external photonic element and the semiconductor die. The boot includes a boot opening, a boot hole, a planar base and an upper wall. The upper wall and the planar base at least partially enclose the photonic inlet. The upper wall may be or comprise a curved surface, or a partially cylindrical surface, or one or more flat surfaces. The boot opening enables the at least partial insertion of the external element into the boot. The base provides a planar surface, wherein the planar surface is placed in mechanical contact with a module when the third preferred embodiment of the present invention is electrically coupled with the module. The boot thereby provides increased mechanical stability of the package when the package is mounted onto the module.
The upper wall, or upper, of the boot of the third preferred embodiment includes a planar top surface that is parallel with the base, and two planar side surfaces that are perpendicular to the base. The base is positioned against and parallel to a mounting surface of the module. The term parallel when applied herein to an orientation between a boot of the present invention and a mounting surface of a module denotes an orientation between the mounting surface and the boot that supports or imposes a parallel orientation between a base of the boot and the mounting surface.
The substantially flat and planar surfaces of the base, the top surface, and the two side surfaces provide surface areas that are easier and less expensive to mark and add signage to than curved or non-flat surfaces. Automated mounting and handling systems more efficiently grasp and position the boot due to the flatness of the base, the top surface, and the two side surfaces, in contrast to prior art housings or boots that are curved or non-planar. The flatness and orientation of the base, top surface, and both side surfaces enable more efficient packing and shipping of the boot of the third preferred embodiment over the prior art.
Certain alternate preferred embodiments of the method of the present invention can optionally enable the assembly of a photonic component that may be assembled with suitable clean room compatible testing and fabrication equipment known in the art. The range of meaning of the term fabrication includes herein suitable processes and process steps known in the art of assembling, wire bonding, trimming, sealing, die attaching, molding, forming, mounting, packaging, marking, and manufacturing photonic components and modules, such as electrical systems, sockets, subsystems, and circuits. The invented VOA package may be mounted onto a module, such as an electrical circuit, a PC board, a system, a subsystem, or a socket, and by using suitable standard device or component mounting equipment and techniques known in the art.
In certain still alternate preferred embodiments of the present invention the photonic element attached to the package is optically coupled and optionally mechanically attached to the package, wherein the photonic element is selected from the group consisting of a wave guide, a planar wave guide, a photonic crystal wave guide, a diffraction wave guide grating, an optical fiber, a collimator, a dual fiber collimator, a multi-fiber collimator, a lens, a diffractive lens, an optical lens, a spherical lens, an aspherical lens, a ball lens, a GRIN lens, a C-lens, a lens system, a mirror, a MEMS-based movable micro-mirror, a flat mirror, a shaped mirror, a diffractive mirror, a grating plate or plates, a laser, a modulator, a photodiode, a VCSEL, and a prism.
Certain alternate preferred embodiments of the present invention include varieties of numbers of pins, from one to twelve, to larger pin counts. The pins may be attached in various linear and non-linear patterns to one or more sides of the package body. The pins may be arranged and shaped to meet an industry packaging standard and optionally to fit into a standard or non-standard socket.
The above summary of the present invention is not intended to describe each illustrated embodiment or every implementation of the present invention. The figures and the detailed description which follow more particularly exemplify these embodiments. Other objects, features, and advantages of the present invention will be apparent from the accompanying drawings and from the detailed description which follows below. The invention will now be elucidated in more detail with reference to certain non-limitative examples of embodiment shown in the attached drawing figures.